Bhagavad Gita 2.14

Those external relations that bring cold and heat, pain and happiness come and go; they are not permanent. Endure them bravely, O Prince!

मात्रास्पर्शास्तु कौन्तेय शीतोष्णसुखदुःखदाः।
आगमापायिनोऽनित्यास्तांस्तितिक्षस्व भारत॥

mātrāsparśāstu kaunteya śītoṣṇasukhaduḥkhadāḥ|
āgamāpāyino'nityāstāṃstitikṣasva bhārata||

English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).